1. Field of the Invention
The present invention relates to a method of manufacturing a single-crystal film, and more particularly to a method of manufacturing a semiconductor single-crystal film on selected areas of an insulating film which is formed on a semiconductor single-crystal substrate.
2. Description of the Prior Art
As is well known, there have been proposed several methods in which a single-crystal film is grown on an insulating film by the use of a laser beam or electron beam.
The first method is as illustrated in FIG. 1a, and comprises forming recesses in the surface of an insulator, such as SiO.sub.2, 1, thereafter depositing an amorphous silicon film 2 and turning the amorphous silicon into a single crystal by irradiation with the laser. It is said that, with this method, the parts of the amorphous silicon film 2 deposited in the recesses are first turned into the single crystal, whereupon the other part is successively turned into the single crystal.
This method, however, is difficult to be put into practical use because, not only difficulty is involved in the control of steps such as the formation of the grooves in the surface of the insulator, but also the characteristics of the single-crystal film produced are unsatisfactory.
The second method is as illustrated in FIG. 1b, and comprises depositing an amorphous silicon film 2 on a predetermined area of the surface of an insulator 1 and turning the amorphous silicon film 2 into a single crystal by irradiation with the laser.
Although only an insular silicon film which is as small as several .mu.m.times.several tens .mu.m can be turned into the single crystal by this method, a non-defective layer having a good crystal orientation is obtained.
This method, however, has the serious problem that the insular amorphous silicon film is melted by the laser irradiation, so the shape collapses. In order to prevent such collapse of the shape ascribable to the laser irradiation, there has been proposed, e.g., an expedient in which the insular amorphous silicon film is surrounded with an SiO.sub.2 film. Since, however, the expedient results in an extremely complicated process, it is difficult to be put into practical use.